Fuel pump



y 3 E. A. ROCKWELL 2 FUEL PUMP Filed Nov. 14, 1929 Patented July 31, I934 um'rizn STATES A ENT orriclz 6 Claims.

The purpose of this invention is to provide an improved means of conducting fuel to a pump for supplying an internal combustion engine, and

conducting fuel from the pump to the engine carbureter which shall be adapted to retain fuel in the pipe line against back flow either directly by gravity or by siphoning when the valves which should prevent such back flow are leaky. It consists in the elements and features of construction shown and described as indicated in the claims.

In the drawing:

Figure 1 is a diagrammatic view showing an engine and main fuel tank from which the fuel is pumped to the engine indicating the relative position of the parts including the pipe lines from the main tank to the pump and from the pump to the carbureter, and the location in said pipe lines of the features constituting the present invention.

Figure 2 is a detail section of the intake end of the pipe line in the main fuel tank for showing an air bleed for preventing siphoning;

Figure 3 is a detail-sectional View of the pump for indicating the fuel lines leading to and from it with their'respective controlling valves.

Referring to the drawing in detail, the engine is indicated as a whole by A, the main fuel supply tank by B, and a pumping apparatus indicated at C for pumping fuel from the main tank to the carbureter indicated at F. The pipe line from the main tank to the pumping apparatusis indicated at D, and the pipe line from the'pumping apparatus to the engine carbureter is indicated at E. Y

The pipe line, D, antecedent to the pumping chamber comprises, preferably proximate to the pumping chamber, a loop seen at D which is drooped so that its bend at the lower end is at a level below the low level of the fuel in the main tank, B. Similarly in the pipe line, E, at any convenient point between the pumping apparatus, C, and the engine carbureter, F, there may be provided a loop indicated at E drooped to the same level as the loop, D of the pipe line, D. The pumping apparatus may be of any character having its'pumping chamber provided with fuel inflow and discharge connections as by the pipes, D and E, respectively, valve-controlled for oneway flow from the fuel source toward the carbureter, said inflow and discharge valves being indicated at 10 and 20, respectively.

The purpose of each and either or both of the drooped loops, D and E is to ensure the retention of a limited amount of fuel pumped from the 5 main tank for supplying the carbureter against (c1. 158 se.4)

back flow toward the main fuel tank, B, which is liable to occur when the engine is at rest by reason of the valves, such asfthe valves, 10 and 20, becoming leaky.

Upon considering the construction as described it will be seen that in the event that the valves of a pumping apparatus do not seat reliably, so that when the'engine is at rest and no suction is developed'by the pump for drawing liquid from the main tank, the entire fuel line may become evacuated by'gravity flow of the fuel back to the main tank if .the entire course of the fuel line froin the tank to the carbureter is above the liquid level of the tank,.but that such backflow will stop at the first point in the line at which the receding level reaches the levelof the liquid in the tank;-and that accordingly the loops, D and-E if they depend below the level of the liquid in the tank, will cause the backfiow to cease before by such backflow the loops are emptied. Accordingly, when the vehicle is standing on level road with the tank liquid level at the lowest point, that is, at the level of the intake of the pipe, D, the'backfiow will cease at the point at which the plane of the level of said intake intersects the up-limb of the loop, E as indicated'at :c on Figure 1. Or if by reason of any defect in the joints of the pumping apparatus, atmospheric pressure mightobtain access to the pump passages anteriorlto the loop, E the evacuation by backflow of the line leading to the pump would cease at the intersection of said plane of the intake with the up-limb of the loop, D as indicated at y, instead of causing in either case the evacuation of the entire line back to the tank, as would happen in the absence of the loops, E and D 'It will be understood upon further considering the operation that since the point to which the backfiow might cause the fuel line to be partly evacuated would normally be determined by the level of the liquid in the main tank, such evacuation would not extend so far back when the tank is full; and in order to ensure that the evacuation shall not extend any further than to the level of the tank, whether the tank be full or partly empty, an air bleed is provided, as indicated at al in the downwardly extending portion, D of the pipe line, D, within the tank, B. The admission of air at this bleed aperture it will be recognized has the effect of making the level at which this aperture is located the determining level for the limit of evacuation of the fuel line when such evacuation would tend to occur by reason of admission of atmospheric pressure past the leaky valves or otherwise in the forward part of the fuel line.

In the construction shown, in which there is provided an air trap seen at G in the fuel line between the pump and the carbureter in which air under pressure is trapped for maintaining the pressure on the fuel line to the carbureter in the intervals of the feeding strokes of the pump, the air bleed at d serves the additional purpose of causing the fuel drawn by the suction of the pump through the pipe line, D, to be somewhat aerated by the air admitted through the air bleed, the air thus carried with the fuel being released after the fuel current passes the discharge valve and serving to replenish the air in the air trap, which in the absence of such provision tends to be absorbed in the liquid with the effect that the air trap becomes eventually filled with liquid, defeating its purpose of maintaining pressure on the fuel line to the carbureter.

I claim:

1. In combination with the carbureter of an internal combustion engine, a pumping apparatus for supplying liquid fuel to the carbureter from a lower source, a main supply tank located distantly from the engine and at a lower level than the carbureter, a pipe line from the pump to the carbureter, a pipe line from the main fuel supply tank to the pump having intake within the tank at the lower part thereof and leading upwardly for emerging from the tank and extending approximately horizontally to the pump, said pipe lines having depending loops respectively between the pump and the main tank and between the pump and the carbureter, said loops being drooped to a level substantially as low as the intake of the fuel supply pipe line in the tank.

2. In combination with the carbureter of an internal combustion engine, a pumping apparatus for supplying liquid fuel to the carbureter from the lower source, a main fuel supply tank situated remotely from the carbureter at a lower level, a fuel supply line from the main tank to the pump having its intake within the tank at the lower part thereof and leading thence upwardly and ferwardly to the pump, said pipe line having a depending loop drooped substantially to the level of the intake of said pipe line in the main fuel supply tank, and having an air bleed aperture at a point within the main fuel supply tank above the hi h liquid level thereof.

3. In combination with the carbureter of an internal combustion engine, a pumping apparatus for supplying liquid fuel to the carbureter from the lower source, a main fuel supply tank situated remotely from the carbureter and at a lower level, a fuel supply pipe line from the main tank to the pump, and a fuel supply pipe line from the pump to the carbureter, one of said pipe lines comprising a depending loop drooped substantially to the level of the intake of the pipe line in the main tank, and an air bleed in the supply line antecedent to said depending loop.

4. An apparatus for supplying liquid fuel to the carbureter of an internal combustion engine on a motor vehicle comprising in combination with a pumping apparatus located approximate to the engine, a fuel supply tank situated on the vehicle remotely from the engine and at a lower level than the carbureter, a fuel supply line from the tank to the carbureter comprising a pipe line leading upwardly from an intake at the lower part of the tank, and having in its course the pumping apparatus, said fuel supply line comprising also a depending loop drooped a substantial distance below the high liquid level of the tank, said pipe line having an air bleed aperture at a point within the tank above the high liquid level thereof.

5. An apparatus for supplying liquid fuel to the carbureter of an internal combustion engine on a motor vehicle comprising in combination with a pumping apparatus located approximate to the engine, a fuel supply tank situated on the vehicle remotely from the engine and at a lower level than the carbureter, a fuel supply line from the tank to the carbureter comprising a pipe line leading upwardly from an intake at the lower part of the tank, and having in its course the pumping apparatus, said fuel supply line comprising also a depending loop drooped a substantial distance below the high liquid level of the tank, said pipe line having an air bleed aperture at a point within the main fuel tank at a point above the high liquid level thereof, said fuel supply line having an air trap at a point in its course between the pumping apparatus and the carbureter.

6. In a liquid pumping system associated with a vehicle supply tank at the rear of the vehicle, a liquid receiving chamber at the front end of the vehicle and at a higher level than said supply tank, a pump at the forward end of the vehicle at an intermediate level with respect to said supply tank and said receiving chamber, a liquid delivery line from said pump to said receiving chamber, a liquid inlet line from said supply tank to said pump, said liquid inlet line being connected to the top of said supply tank and extending downwards thereinto for intake at its lower end adjacent the bottom of said supply tank, and said liquid inlet line between said tank and said pump including a portion dropped to a level corresponding to the bottom of said supply tank.

EDWARD A. ROCKWELL. 

